Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Per Share data, unless otherwise specified	Oct. 25, 2014	Jul. 26, 2014
Statement of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 276	$ 265
Preferred stock, par value (in dollars per share)	$ 0	$ 0
Preferred stock, shares authorized (in shares)	5	5
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	20,000	20,000
Common stock, shares issued (in shares)	5,109	5,107
Common stock, shares outstanding (in shares)	5,109	5,107